Digital Out - Ref change

Discussion in 'General Electronics Chat' started by jismagic, Jun 2, 2014.

  1. jismagic

    Thread Starter Member

    Sep 7, 2013
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    Whats the easiest/efficient way to take a digital out from a micro and then change the reference - (0-5V) to (0-12V) or (0-18V). Also increase the source and sink current.

    thanks
    jis
     
  2. pwdixon

    Member

    Oct 11, 2012
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    Use a transistor.
     
  3. jismagic

    Thread Starter Member

    Sep 7, 2013
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    I forgot to mention - i do not want to build a circuit, but use something that is already available. Use an IC which can do it for me, or a module i can buy easily or replace easily

    thanks
    jis
     
  4. absf

    Senior Member

    Dec 29, 2010
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    This type of circuits is usually known as voltage level shifter and is used between 3.3V and 5V logic devices. You may do a search on eBay or Sparkfun to see if such product is available using keyword "voltage level shifter".

    A cmos logic chip 'HCF40109BE' is also a logic shifter capable of 0-3V to 0-18V. It has separate Vcc and Vdd. You can download the datasheet of this chip from the net easily.

    Allen
     
    Last edited: Jun 2, 2014
  5. pwdixon

    Member

    Oct 11, 2012
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    A transistor solution will allow for a wide range of level shifts and need be no more than a transistor and perhaps a resistor. That's got to be easier than wiring up an IC surely?
     
  6. pwdixon

    Member

    Oct 11, 2012
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    One of these chips might not fulfill the requirement to higher output current though.
     
  7. absf

    Senior Member

    Dec 29, 2010
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    Quite true. But the OP never specify how much current he wanted to source ot sink. A transistor can either sink or source current but not both. Unless it is connected in a totem-pole way.

    May be the OP should spell out his need in more details.

    Allen
     
  8. jismagic

    Thread Starter Member

    Sep 7, 2013
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    I see a need of 10mA normally. In some case i also see a maximum of 70mA.

    thanks
    jis
     
  9. MrChips

    Moderator

    Oct 2, 2009
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  10. pwdixon

    Member

    Oct 11, 2012
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    source or sink?
     
  11. jismagic

    Thread Starter Member

    Sep 7, 2013
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    Sink current.
     
  12. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    The ULN2001 gets you 7 translators. Each is a darlington transistor arrangement, so it acts as a logical inverter and each output needs a pull up resistor. Also, it does not pull down all the way to GND. Low outputs sit at 0.65-0.8V depending on current.

    ak
     
    absf likes this.
  13. pwdixon

    Member

    Oct 11, 2012
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    However, a single mosfet transistor could be selected for whatever minimum voltage pulldown you'd like to chose based on current loading and RdsON. And you wouldn't need a pullup resistor on the input or output either.
     
    absf likes this.
  14. MaxHeadRoom

    Expert

    Jul 18, 2013
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    There is also the ULN2803/5 that provide 8 drivers.
    For a single, the 2n7000 should work.
    Max.
     
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